Spreader rolls are used to address the problem of removing wrinkles from a rolled web of a flexible material, such as paper, cloth, film, foil, plastics, and nonwovens. Conventional spreader rolls typically include a bowed or unbowed stationary shaft on which an elastomer sleeve is rotatably mounted. One area of the sleeve outer surface is expanded with respect to an opposite area such that as the web material is passed across the sleeve surface from the less expanded to more expanded portion, the web is similarly expanded to remove wrinkles.
While these spreader rolls are useful in removing wrinkles from the center of the web, often the opposite lateral edges of the web remain wrinkled since the spreader rolls do not properly expand the web of material along its edges. These wrinkled edges therefore must be trimmed or otherwise removed, which creates a substantial amount of waste. In addition, the amount of expansion or contraction in most existing spreader rolls is difficult to adjust and requires a significant amount of machine downtime.
U.S. Pat. No. 5,461,760 issued to L. Damour represents a significant advance in the art in that it discloses a sleeve stretcher assembly that allows for proper initial adjustment of the tension on the resilient flexible sleeve of the roller assembly using only ordinary tools. This sleeve stretcher assembly thus allows the resilient sleeve member to be adjusted as needed, and in addition the sleeve member can be replaced when worn without requiring the entire roller assembly to be returned to the factory for proper mounting and initial adjustment of a new sleeve. As a result, the amount of machinery downtime was very significantly reduced and associated increases in productivity were realized.
In the Damour '760 patent, bores are provided in the ends of the stationary shaft forming part of the roller assembly, in which bores a slide rod is secured. A hub member is then pivotally connected to the slide rod by a pivot means. The present inventor has now developed an alternative arrangement for incorporating a slide mechanism into an end cap assembly that does not require bores to be formed in the ends of the stationary shaft, and that is less expensive to manufacture. The present invention therefore provides an end cap assembly including a pivot arm that better clamps and retains the end of a rubber sleeve in the clamping assembly. In addition, the present invention provides a pre-load assembly that allows the tension on the ends of the roller sleeve to be set to an initial setting and then adjusted or tightened later without any machine downtime using only standard tooling, and whereby the adjustments can be made on each end of the roller assembly independently.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.